The present invention relates to an adapter for a humidifier used in respiratory apparatus.
Inhalation therapy is frequently used for patients suffering from such diseases as emphysema, stroke, heart stoppage, drowning, and a variety of other applications which require the administration of either pure oxygen or a high percentage of oxygen or other medicaments administered through inhalation therapy. Humidifiers are employed in the respiratory apparatus. The patient inhales a gas-liquid mixture from the humidifier, which is effective in moistening the gas that is passed through the humidifier and discharged therefrom in a manner to introduce the moistened gas, such as oxygen or air, into a person's respiratory system. The gas is humidified so as to prevent dessication of the respiratory tract or membranes during treatment over a prolonged period of time.
There has been a problem in the past with medical humidifiers in reliably determining when humidified gas was inadvertently cut off from the patient. This often happened when the oxygen tube leading to the patient's mask became kinked. Thus, while it appeared that the patient was still receiving the oxygen or other humidified gas, he was in effect cut off from his inhalation therapy treatment.
It has been proposed to use various check valves or pressure relief valves in a humidifier to avoid an excessive pressure buildup that might break tubing joints, etc. from their connections. When such a pressure relief valve does open to release pressure, it is important that the attending medical personnel be aware of it. This is so he can correct the obstruction causing the pressure buildup and quickly get the patient back on his prescribed inhalation therapy. Previous inhalation therapy apparatus involved a spring biased check valve that exhausted released gas into a knife edge whistle such as a common toy whistle. However, the gas flow rates in a medical humidifier are sometimes too slow to cause a noise with such a whistle. Also, at very low pressures of between 2 and 4 psi above atmospheric, these knife edge whistles do not always operate reliably.
U.S. Pat. Nos. 4,061,698 and 4,100,235 disclose humidifier-nebulizer apparatus having an adapter head that includes control valve means movable to discharge a nebulized gas-liquid mixture from the adapter head during a nebulizing mode of operation and adjustable to introduce liquid oxygen into the reservoir in a manner to effect discharge of humidified oxygen through a discharge port of the liquid reservoir of the apparatus. However, these apparatus do not include an audible relief valve means which serves as an audible alarm to indicate an above normal pressure in the humidifier to alert an attendant of his condition.
Sherman, U.S. Pat. No. 4,134,940, discloses a humidifier adapter comprising two oppositely facing, independently movable, internally threaded pieces for connection to the gas conduit and the water bottle, a body piece intermediate the two end pieces with an axial hose for holding a spike, a set screw transfixing the body piece, two pressure sealing "O" rings, and an audible duck bill valve with retaining screw and flange upon which the valve sits. An internal pressure chamber is located between the spike and internal diameter of the body piece which connects with the water bottle, which body piece is transfixed by the duck bill valve.
Kankel et al, U.S. Pat. No. 4,039,639, discloses a humidifier comprising a flap valve for emitting an audible alarm when excessive pressure exists in a nebulizer device. A flexible tube is used to connect an oxygen diffuser immersed in liquid to a source of oxygen.
McPhee, U.S. Pat. No. 3,807,445, discloses an audible pressure relief valve for a medical humidifier. The valve has a rubber disc that is dimensionally tuned to vibrate against a valve seat and emit an audible sound at gas flow rates of 3 to 15 liters per minute and pressures of 1 to 5 psi above atmospheric pressure.
Ollivier, U.S. Pat. No. 3,867,934, discloses a pressure monitor for use with a lung ventilator. The monitor is connected to a pneumatically-operated warning device which may be audible, visible, or both.
Adolphsen et al, U.S. Pat. No. 2,267,009, discloses an oxygen inhaling assembly including a tube for oxygen flow. If the tube becomes clogged, pressure will build up in a casing and a diaphragm connected to the casing will begin to lift, releasing gas from the casing for passage through a duct to the atmosphere. In this case, the diaphragm will vibrate, emitting a sound similar to that of an air horn.